1. Field of the Invention
The present invention relates to an imaging apparatus having a distortion correction function, and an imaging method used in the imaging apparatus.
2. Description of the Related Art
In recent years, an increasing number of imaging apparatuses such as digital cameras have a live-view display function (also referred to as through-image display function). The live-view display function is a function of displaying an image, which is obtained by performing continuous imaging by an imaging device, on a display section in real time. The live-view display function enables the user to check composition in photographing and the like, by using the display section provided on the back surface of the digital camera. In addition, recently a function of the imaging device has also been improved, and there are imaging devices which can capture only signals corresponding to a partial range of the imaging devices. In recent years, enlarged live-view display operation has also become possible, by using the function of the imaging device described above. The enlarged live-view operation means operation of enlarging a partial range of the image displayed by the live-view display function and subjecting the part to live-view display, when the partial range of the image displayed is designated by the user.
The imaging apparatuses such as digital cameras generally have a lens to form a subject image on the imaging device. Since the lens has distortion, the subject image formed on the imaging device through the lens has a distorted shape with respect to the shape of the subject to be actually obtained. In recent years, various proposals have been made with respect to imaging apparatuses which have an electronic distortion correcting function of electronically correcting a distorted image obtained from the imaging device into an image with no distortion. For example, in Jpn. Pat. Appln. KOKAI Pub. No. 2005-45513, a desired small area in an image is read out and distortion correction for each small area can be performed. By using the method of Jpn. Pat. Appln. KOKAI Pub. No. 2005-45513, distortion correction can be performed also in the enlarged live-view operation.